I prefer prevention to cure and therefore normally check/clean my camera sensor either before I put it away or before take it out for the day.
To be fair though I've only ever lost a few shots to dust bunnies back when I had Canon DSLR's. Other than that bunnies were common and I remember coming back from Kazakhstan with my 5D and Sigma 50mm which never left the camera and still sitting up until daft AM cloning out bunnies on hundreds of shots, I'm glad those days are gone. The few shots I lost were macro shots of a spider and the bunnies were so strategically placed that rescuing the shots was beyond my PS capabilities so I just cursed the camera and deleted the shots.
These days I do multiple lens changes in the street, hills, woods or at the beach... as demonstrated by some of the shots I've posted here and all with greatly fewer issues than I ever had even when not changing the lens on my Canon DSLR's